In a manufacturing process of semiconductor devices, e.g., an etching process or a film forming process is performed by using a plasma.
The plasma processing using the plasma is generally performed by a plasma processing apparatus. The plasma processing apparatus includes, in a processing chamber, an upper electrode to which a high frequency power for generating the plasma is applied, a susceptor for supporting a substrate, and the like. Further, an inside of the processing chamber is depressurized to a predetermined pressure, and a processing gas is supplied into the processing chamber, and then, the high frequency power for generating the plasma is applied to the upper electrode to etch a film on the substrate by the plasma generated in the processing chamber.
Even when the plasma processing is performed under a high temperature condition to generate the plasma, it is required to constantly maintain a process condition in which the substrate is processed, e.g., a temperature of the substrate. On this account, the susceptor for supporting the substrate is temperature controlled, for example, by being provided with a circulating coolant to control the temperature of the substrate.
In case a top surface of the susceptor is smaller than that of the substrate, a peripheral portion of the substrate is outwardly extended beyond the top surface of the susceptor (for example, Japanese Patent Laid-open Application No. H11-121600). Consequently, it is prevented that the top surface of the susceptor is exposed to the upper electrode side to be etched by the plasma or the like during the etching process.
However, in case the peripheral portion of the substrate is extended beyond the susceptor as described above, during the process, a large amount of heat is applied to the peripheral portion of the substrate, and the peripheral portion of the substrate is not cooled sufficiently. On this account, the temperature of the substrate mounted on the susceptor becomes higher as a position on the substrate approaches the peripheral portion of the substrate, and thus, the in-surface temperature is not maintained uniformly. In case the temperature of the substrate surface is not uniform, for example, an in-surface etching uniformity is deteriorated, and thus, for example, a size of a line width of a central portion of the substrate becomes different from that of the peripheral portion.